A communication condition in a radio network changes depending on the distance to a base station, a surrounding environment, time and so on. Accordingly, an administrator or an operator of the radio network must always comprehend quality conditions in various areas or cells in the radio network and strive to improve the radio quality.
A straightforward method for measuring the quality condition in the various areas is that the operator visits these areas to measure electrical waves therein. This method is called a Drive Test. However, if the operator investigates all the areas periodically and conducts the drive test to determine which areas are to be improved, there is a risk that the associated cost may become substantially high.
From this viewpoint, a technique is currently being discussed for causing user equipments or user apparatuses residing in the areas instead of the operator to measure the radio quality therein and report measurement results to the operator. This technique is called a Minimization of Drive Test (MDT). The MDT is described in Non-Patent Document 1, for example.